Kodak is one of the first companies to produce and introduce 3D imagery where the image is bonded to a lenticular material after the image is printed. U. S. patent application Ser. No. 885,411 entitled "A Method of Adapting Scan Print Images with Lenticular Face Plates" by Roy Taylor addresses this architecture. A key element of laminating lenticular material to a developed image on film is the obtaining of an accurate alignment between the film image and the lenticular material. This element has been covered in U.S. patent application Ser. No. 885,699 entitled "Electronically Printed Integral Photography System" by Roy Taylor and Sergei Fogel.
Our experience with laminating film to lenticular material indicates however that there can be variations in the spacing of lens elements from one piece of lenticular material to another or in the spacing of image elements from one piece of film to another. Variations in lenticular material can arise from variations in shrinkage (lenticular material has a typical shrinkage after molding of 0.1% to 1% of the material size). While the average value of this shrinkage can be predicted and compensated for, variations in the shrinkage from piece to piece of the lenticular material or variations in the shrinkage of the film which is matched against the lenticular material may cause a significant loss of image quality.
The scale of allowable variations may be quite small. For example, an image which is 10" wide and has 70 lenticules per inch with 15 views per lenticule, has 10,500 views across its width. For the highest image quality the maximum allowable misregistration is plus or minus half a view allowing a differential shrinkage between the lenticular material and the film must be kept to plus or minus 0.005%.
(As already indicated, lenticular materials typically shrink in the range of 0.1% to 1%. Based on the considerations already referred, maximum allowable shrinkage variation must be 1/20th to 1/200th of these vales. In fact, the actual allowable variation for the lenticular material would even be less than this since the total variation must be shared with the film which has a variance of its own.)
Considering variations in material, variations in molding practices and other sources of variation, maintaining variation of the order of 0.005% in shrinkage cannot always be guaranteed. Therefore for the highest quality images some method of matching the pitch (spacing) and in some cases even the curvature (see FIG. 4) of the lenticular material to the film becomes necessary.
The present invention is directed to alignment apparatus and associated methods by which this may be done to differentially match the size or scale of the lenticular material to exposed film on a piece by piece basis.